Effect of Oral Administration of Freshly Pressed Juice of Echinacea Purpurea on the Number of Various Subpopulations of B- and T-Lymphocytes in Healthy Volunteers: Results of a Double-Blind, Placebo-Controlled Cross-over Study**‪.‬

Abstract Background: In a recent double-blind placebo-controlled crossover-study the "immune stimulatory" effects (activation of macrophages leading to enhanced phagocytosis and production of several cytokines) of Echinacea purpurea preparations (EPP) which were observed in vitro experiments and following parenteral administration could not be confirmed following oral application of the drug in healthy volunteers. The aim of the present study was to investigate whether or not oral EPP has any effect on important lymphocyte-subpopulations.